Temporal trends of persistent organic pollutants (POPs) and perfluoroalkyl substances (PFAS) in Adèlie penguin (Pygoscelis adeliae) eggs from the Ross Sea (Antarctica), including their relationship with climate parameters.

Temporal trends of contaminants represent an important tool to evaluate the effectiveness of chemical restriction measures. In this work, 50 eggs of Adèlie penguin (Pygoscelis adeliae) collected along the Ross Sea coasts from 1997 to 2021 were analysed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), perfluoroalkyl substances (PFAS). Some PCB congeners showed a significantly decreasing trend, whereas HCB and p,p'-DDE indicated decreasing but not significant trends, potentially related to the unintentional production of HCB and ongoing use of DDT, even if a contribution from climate-driven remobilisation mechanisms may also play a role. PBDE-47 also indicated a decreasing but not significant trend, which might be explained by the more recent global restriction. PFAS trends agreed with what has been previously observed in the Arctic, i.e. significantly decreasing perfluorooctane sulfonate (PFOS) according to its global ban and increasing long-chain perfluorinated carboxylic acids (PFCAs). Correlations with selected climate parameters showed an association between PBDE-47 and sampling year precipitations. To our knowledge, this work represents the longest time trend study of pollutants in penguins from the Ross Sea and the first one reporting PFAS. It highlights the importance of global regulations for the contaminant developments in polar ecosystems.